Disposable diaper



1953 w. A. HERMANSON ET AL 2,649,859

DISIPOSABLE DIAPER Filed Feb. 10, 1951 INVENTOR. W1 I114 01 A He ram"90: BY crqlqfffirmu 30'? Patented Aug. 25, 1953 2,649,859 DISLPOSABLEDIAPER William A. Hermanson, Brookline, and

Gerald I. Hermanson, Newton, Mass.

Application February 10, 1951, Serial No. 210,402

The present invention relates to disposable diapers in which paper andplastic materials are combined together.

It has been conventional to make disposable diapers out of combinationsof cellulose wadding and a backing sheet which is supposed to be waterrepellant with the backing sheet adhered to the cellulose by adhesivemeans. The customary paper used for making the backing of a so-calleddisposable diaper water repellant is usually a wood pulp-sheet with aWax size, starch size, resin size, or a silicon film' of mono-molecularthickness. The papers used'average .0075 in thickness. Due to thethickness of this paper it is never soft nor completely flexible as abacking sheet. Furthermore, when the so-called diaper or pad is appliedto the infant the action of the child in kicking its legs is suflicientto induce capillary action in the fibers of the sheet and leakage of thecontents of the diaper takes place through the supposedlywater-repellant backing. Furthermore, the thickness of the, paperbacking is such that the inguinal spaces are overloaded and thebulkiness of this type of backing. causes excess chafing and developserythema.

Another disadvantage of a wood pulp sulphite backing sheet is theshortness of the fibers, which range from inpalpable'dust to threemillimeters in length. Since it is the purpose of an. integrated babydiaper that it shall completely replace a woven cloth diaper and yet bedisposable, it must be pinned at the babys waist in the same manner as awoven diaper. The short wood pulp fibers are not long enough to hold asafety pin with that degree of safetywhich is necessary for the duty thediaper must perform and the disposable diapers now sold frequently breakthrough the pins and cause considerableinconvenience by falling apartand opening. I

Disposable diapers being currently marketed are also spoken of as beingdisposable in toilet bowls but the thickness of a water repellantbacking paper having a caliper of .0075 makes it imcreped, cellulosesheets with a water-proof backing film of plastic material or itsequivalent which extends around the sides of the creped cellulose sheetsand is adhered to them and to the top surface sheet.

It is the further purpose of this invention to 10 Claims. (Cl. 128-287)v in thickness.

provide a disposable diaper in which the softer bulkier creped cellulosesheets may readily be separated from a ,very thin backing sheet or isactually separated in parts so that the parts may be disposed ofseparately. In addition the backing sheet may be of such thin material,of the order of .001 inch, and be crushed into such a small Volume thatit will readily flush down the drain.

The invention will be more fully understood from the specification setforth below when taken in connection with the drawing illustrating anembodiment thereof in which:

Figure 1 shows in perspective view the present invention.

Figure 2 is an enlarged section taken on the line 22 of Figure 1;

Figure 3 is a modified section corresponding to the section of Figure 2;and,

Figure 4 is a still further modified section corresponding to thesection of Figure 2.

The disposable diapers shown in the figures have a top sheet I which issoft, yieldable and which,,as mentioned above, is treated to have wetstrength and yet be both absorbent and permeable. This sheet may be ofpaper which is made of long vegetable fibers of high porosity such asabaca fibers or abaca and synthetic cellulose fibers blended together orsynthetic cellulose fibers bonded together with wood pulp It isimportant that the top sheet be thin yet both soft and strong andcapable of supporting pins through the same without tearing. This sheetmay range from .00125 to .0015 inch Beneath the top sheet are from fourto eight creped cellulose sheets 2 which after creping should have athickness from .002

,to .004. The backing sheet 3 is preferably a bility, softness and whichare waterproof.

On the whole a polyethylene sheet having a thickness of from .005 to.0015 inch is suitable for this purpose. These sheets are waterproof andare folded around the sides as indicated by 4 and 5, Figure 2, of thecreped sheets 2 and extend for a width of to of an inch just beneath thetop sheet I on the sides as indicated at 6 and 1 respectively.

sheet I at its sides is also sealed to the top surface of the backingsheet in the side extensions which fold underneath this sheet. Thediaper, therefore, is held together as a single sheet by the side sealsonly. Polyethylene for this purpose is highly useful since it providesits own thermoplastic sealing means and all that is necessary to form aseal at the side edges is to run thediaper through heat sealing rollsalong its sides. If desired, the whole sheet may be run through a heatsealing roll in which the lower creped sheets will be sealed to thebacking sheet 3. On the whole, however, it has certain definiteadvantages to form the seal only along the side edges as will presentlyappear.

In place of using a thermoplastic, water-proof backing sheet as justdescribed, a water-proof sheet of non-thermoplastic qualities could beused in which case it will be necessary to apply some adhesive along theside edges of the backing sheet or the side edges of the creped sheetand the underside of the top sheet to complete a seal along the sideedges.

From the above description, it will be noticed that the ends of thesheet, that is the end 8 Y and the end 9 (Figure l) are open, that is,they are not bound. By permitting the ends of the sheets to remain openand sealing the sheets only at their sides, when the diaper is to bedisposed of, the top sheet i and creped sheets 2 may be grasped at theend B or 9 and the complete sheet I with the inner creped sheets 2 maybe torn from the backing sheet 3 and readily disposed of in the toiletbowl.

The water-proof backing sheet which is a very thin film may separatelybe disposed of in the same way since this sheet will crumble into a verysmall volume.

Where the backing sheet is a thermoplastic heat sealing film sulficientheat may be applied for a long enough period to seal the creped sheetsforming the center of the pad along these side margins together. Thismay be done without impairing the backing sheet since most of the heatseal may be effected by the turned in top margin of the backing sheet.

The construction as described above is the preferred construction in thepresent invention since it provides a cheap, disposable diaper. Ifdesired,

the backing sheet may be made a composite sheet such as shown in Figure3 comprising a plastic, waterproof film I laminated together with asheet I I of the same type as the sheet I in Figure l or laminatedtogether with a thin creped absorbent cellulosic sheet. This laminatedsheet may be folded up around the sides and under but preferably overthe top soft sheet I2 which also is the same type of material as thesheet I. The plastic film sheet It will, therefore, extend over thesheet I2 on the edges and the edges may be sealed together, therefore,similarly as in the construction in Figure 2 by applying the heatingrollers to the side edges in the same way as has been described.

One of the chief advantages in the construction as described is that thewaterproof backing element extends around the sides and, therefore,provides a seal against leakage along the side edges of the diaper.

The diaper in Figure 3 may also be readily torn apart so that the easilydisintegrating cellulose sheets can be disposed of separately from thebacking sheet which should normally be crushed to a smaller volume indisposal.

A thermoplastic seal may be made by the thermoplastic backing sheet ofthe side edges of the creped sheets and these may be sealed to the facesheet along the sides to the edges or margin of the top face sheet. Ifdesired the creped sheets may be sealed along these sides only to facesheet and not to the back sheet so that in disposing of the diaper itwill be necessary only to grasp the top sheet and tear it away from thebacking sheet, the creped sheets clinging to the face sheets will staywith it as it is torn free.

An advantage of the construction shown in Figure 3 is that when theplastic film is laminated to a sheet of the type described, a very thinfilm may be used. This film may be in the range of .0005 inch which isthe limiting thinness of plastic film which could otherwise be used.

Where it is desired to have the creped sheets cling to the top facesheet, an adhesive may be used at the edges of the creped sheets in theconstruction shown in Figure 3 or in the construction shown in Figure 2more pressure may be applied to the top rollers at the margins 6 and Ito make the plastic film partly penetrate the margins of the crepedsheets and spread a seal at the sides of the top sheet I with the edgesof the creped sheets.

In the construction of Figure 4, the plastic film I3 and the soft thinsheet I4 which may be the same sheet as in Figure 3 are laminated, castor pressed together and applied at the bottom, around the sides I5 andI6 and over the top marginal edges I! and I8 respectively of the topsheet I9 which may be of the same structure and texture as the sheet I4.Instead of extending the sheet I9 to the very side edges of the enclosedcreped sheets 20, it stops short of the side edges of the creped sheetsand permits the thermoplastic film I3 on its turned in margin to comedirectly in contact with the creped sheets 20 and form a seal for theedges of the creped sheets when heat is applied in this region. At thesame time a further thermoplastic seal may be made along the marginsbetween the top sheet I9, the turned over margins I1 and I8 and thecreped sheets beneath the same.

Having now described our invention, we claim:

1. An integrated disposable diaper comprising a top surfacing websubstantially of vegetable fibers, having wet strength to a high degree,permeability and absorptivity, and having a caliper not in excess of.0015 inch, a number of creped cellulose thin plies and a water-proofbacking sheet having a caliper not in excess of .004 inch, heat sealedto the surfacing web.

2. An integrated disposable diaper comprising a top surfacing websubstantially of abaca fibers, synthetic fibers, and wood fiber havingwet strength to a high degree, permeability and absorptivity, and havinga caliper not in excess of .0015 inch, a number of creped cellulose thinplies and a water-proof backing sheet having a caliper not in excess of.004 inch, heat sealed to the surfacing web.

3. An integrated disposable diaper comprising a top surfacing websubstantially of synthetic fibers, and wood fibers having wet strengthto a high degree, permeability and absorptivity, and having a calipernot in excess of .0015 inch, a number of creped cellulose thin plies anda water-proof backing sheet having a caliper not in excess of .004 inch,heat sealed to the surfacing web.

4. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped cellulose thin plies and a thin backingsheet, thermo-plastic water-proof material extending around the sides ofthe creped cellulose plie and under the margin of the top surfacing web,said thermo-plastic material sealing together along the side margins ofthe diaper the top surfacing web and the creped cellulose thin pliestogether to the backing sheet.

5. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped cellulose thin plies and a thin backingsheet, thermo-plastic water-proof material extending around the sides ofthe creped cellulose plies and under the margin of the top surfacingweb, said thermo-plastic material sealing together along the sidemargins of the diaper the top surfacing web and the creped cellulosethin plies together to the backing sheet, said backing sheet having acaliper being of not more than .004 inch in thickness.

6. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped cellulose thin plies and thin backing sheet,thermo-plastic water-proof material extending around the sides of thecreped cellulose plies and under the margin of the top surfacing web,the marginal edge of the thermo-plastic sheet under the surfacing webserving as a seal for sealing together the surfacing web and thethermoplastic marginal edge as well as the creped sheets lying adjacentto said marginal edge.

7. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers havin a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped, cellulose, thin plies and a thin backingsheet having a caliper not in excess of .004 comprising anouter sheet ofthe same material as the top surface Web and an inner sheet ofthermo-plastic film, the two sheets being coextensive with the sidemar-gins thereof, extending around the creped cellulose thin plies andover the top surfacing sheet along the side margins in contact with thesurfacing sheet serving as a thermoplastic seal for the top surfacingsheet to the margin of the backing sheet and to the cellulose webs.

8. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped, cellulose, thin plies and a thin backingsheet having a caliper not in excess of .004 comprising an outer sheetof the same material as the top surfacing web and an inner sheet ofthermo-plastic film, the two sheets being coextensive, with the sidemargins thereof, extending around the creped cellulose thin plies andover the top surfacing sheet along the side margin thereof, saidthermo-plastic sheet along the side margin in contact with the surfacingsheet serving as a thermo-plastic seal for the top surfacing sheet tothe margin of the backing sheet and to the cellulose Webs, said topsurfacing sheet being shorter in width than the creped cellulose thinplies allowing a margin along the sides of the creped sheets wherein thecreped sheets come in contact with the margin of the thermo-plasticsheet whereby a direct seal is obtained between the thermoplastic sheetand said creped sheets.

9. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of Wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped, cellulose, thin plies and a thin backingsheet having a caliper not in excess of .004 comprising an outer thincreped absorbent cellulose sheet and a film on the inside surfacethereof of thermo-plastic material, said backing sheet extending aroundthe sides and over the top side margins of said creped cellulose plies,said top surfacing web lying under the backing sheet along said top sidemargins, said film acting to heat seal the top surfacin and thecellulose plies to the backing sheet.

10. A disposable diaper comprising a top surfacing web substantially ofvegetable fibers having a high degree of wet strength, permeability andabsorptivity and having a caliper not substantially in excess of .0015inch, a plurality of creped, cellulose, thin plies and a thin backingsheet having a caliper not in excess of .004 comprising an outer thincreped absorbent cellulose sheet and a film on the inside surfacethereof of thermo-plastic material, said backing sheet extending aroundthe sides and over the top side margins of said creped cellulose plies,said top surfacing web lying under the backing sheet along said top sidemargins, said film acting to heat seal the top surfacing and thecellulose plies to the backing sheet and means adhering together thecreped cellulose plies with the top surface sheet.

WILLIAM A. HERMANSON. GERALD I. HERMANSON.

References Cited in the'file of this patent UNITED STATES PATENTS NumberName Date 1,930,114 Straus Oct. 10, 1933 1,971,606 Grant Aug. 28, 19342,002,368 Fancher May 21, 1935 2,019,842 Bussing et al. Nov. 5, 19352,119,610 Tasker June 7, 1938 2,560,332 Crane July 10, 1950

